Ankylosaurus is the largest known armored dinosaur, reaching up to 6.25 meters (20.5 ft) in length, 1.5 meters (4.9 ft) in width and 1.7 m (5.6 ft) at the hip. This length was proposed by American paleontologist Kenneth Carpenter and is based on the largest known skull (specimen NMC 8880), which is 64.5 cm (25.4 in) long and 74.5 cm (29.3 in) wide. The smallest known skull (specimen AMNH 5214) is 55.5 cm (21.9 in) long and 64.5 cm (25.4 in) wide, the specimen is estimated to be 5.4 m (17.7 ft) in long and about 1.4 m (4.6 ft) wide. Some authors estimate the body length of an adult ankylosaur from 7 m (23 ft) to 8-9 m (26.2-29.5 ft). The ankylosaur was covered from head to tail with dense, bony armor, consisting of individual plates. Large triangular horn-like protrusions protected the base of the skull. Osteoderms ranged from 1 cm (0.4 in) in diameter to 35.5 cm (14.0 in) in length and varied in shape. The ankylosaur's tail was massive and ended in a heavy bony tuber. In the specimen (AMNH 5214) it measures 45 cm (18 in) wide.

Scientists believe that the thickening at the end of the tail was formed from bony nodes, originally covered with skin, which, as they grew, were connected very tightly, so that the end of the tail was very rigid and durable. The movements of the header were concentrated and controlled by special muscles located at the base of the tail and usually used to move the hind limb back when walking. With the help of these muscles, the animal could move its tail from side to side.

Nutrition and lifestyle

Their appetite was excellent, as evidenced by the size of their digestive organs. The squat build made it possible to pluck low-growing vegetation with ease. The powerful bird-like beak of the ankylosaur helped to bite off even hard tree branches.

In that world, groups of animals moved measuredly across rocky plains in search of green oases that promised cherished rest and watering holes. Despite their slowness, in moments of danger, ankylosaurs acted decisively, clearly following the instincts developed by nature. This helped protect even from large theropods, for example, the tyrannosaurs that lived at that time.

A serious surge in popularity for this lizard was observed at the beginning of the era of space technology, after the presentation of its artificial full-size model at the 1964 World's Fair in New York.

Protection

Ankylosaurus mainly relied on 3 things: camouflage, armor, and a mace. Osteoderms and spines on its shell could perfectly help hide from predators in fallen leaves or dense vegetation. If it was not possible to hide, and the predator noticed the ankylosaur, then it would dig a hole in the ground with its powerful paws and lie down in it to protect its soft belly. He swung his tail from side to side, trying to scare away the predator, and if he came closer, the ankylosaur could hit him with great force with his mace. Such a blow could knock out several of the enemy's teeth or even break a leg.

Mace on the tail

Ankylosaurus tail club, American Museum of Natural History

The famous ankylosaur tail club also consisted of several large osteoderms that were attached to the last few caudal vertebrae. It was heavy and rested on seven vertebrae at the tip of the tail, which were firmly connected, forming a rigid rod at the base of the club. Tendons were attached to these vertebrae, which provided reliable protection. These tendons were somewhat stiff and lacked elasticity, which, when the tail was swung, allowed a significant force impulse to be transmitted to the end of the tail. Most likely, it was an active defensive weapon, which had a significant destructive force and could break the attacker’s bones or knock over to the ground, even the largest predators, including the tyrannosaurus. In addition, when attacking two-legged predators, the position was much less stable than that of the ankylosaur. All this most likely doomed carnivores to a long life painful death. A 2009 study found that "large tail bulges could generate enough force on impact to break bones, but small bulges did not have this ability" and that "tail swinging is a highly plausible ankylosaur behavior, but is not known to have been used either the tail during interspecies fighting or intraspecific fights, or in both cases.” It was also suggested that the tail club was, as it were, a “false target” for the predator, since from a distance he could mistake it for the head. However, this hypothesis is currently widely disputed.

In popular culture

Since the Ankylosaurus was first described in 1908, the public has known it as the archetypal armored dinosaur, and thanks to its memorable appearance and the public's increased interest in dinosaurs, it has remained a part of popular culture around the world for many years. The ankylosaur's fame was greatly enhanced by its life-size reconstruction, which appeared at the 1964 World's Fair in New York. Ankylosaurus is mentioned in the 1955 Japanese kaiju film Godzilla Strikes Again as the ancestor of the mutant monster Anguirus. Anguirus, there are many variations in pronunciation and spelling). From 1955 to 2004, Anguirus appeared in seven Godzilla films. He has also appeared regularly in books, television shows, and video games.

Classification of ankylosaurs

According to the generally accepted classification, belong to the group of ankylosaurs: Scelidosaurus, Nodosaurus, Acanthopholis, Polacanthus, Sauropelta, Paleoscincus, Panoplosaurus, Talarur, Euoplocephalus and the Ankylosaurus itself.

Rice. 1 – Ankylosaurs

Scelidosaurus was the first in the chain of armored dinosaurs. It arose 100 million years earlier than the ankylosaur, reached 3.5 m in length, and fed on palm-shaped cycads and ferns. The bony plates and spines of its shell formed 7 rows along the body, so the name of the ancestor of the ankylosaur translated from Latin means "dismembered lizard".

Nodosaur possessed slim body, a narrow head, a loose, rather weak armored shield and a pointed tail. The nodosaur owes its name to the large nodes that covered the skin of the lizard.

Acanthopholis reached 5 m in length, had a sharp tip on the tail, and its shoulders and neck were dotted with rows of short spines.

Polacanthus had a similar structure and differed only in the size of the double-sided spines, which were twice as large as those of Acanthopholis.

The largest animal groups of ankylosaurs arose during the last period of their existence on Earth.

Sauropelta had strong solid armor and was particularly massive, as it weighed 3 tons and reached 7 m in length.

Paleoscincus, nicknamed "ancient lizard", And panoplosaurus, whose name stands for "lizard with a solid tail", lived on the planet at the end of the era of dinosaurs and were considered real giants.

Talarur reached 6 m in length, had a strong solid armored shield and a tail, the tip of which resembled a mace. The remains of a dinosaur discovered in Mongolia indicate that the thickness of the bony armor plates was 5 cm.

Euoplocephalus means "typical armored head". This large ten-meter ankylosaur could easily fend for itself thanks to its powerful tail. Its back part was made of ossified tendons, which turned the limb into a kind of rigid handle with a thickening at the end, which could be used to deliver dangerous targeted blows.

The most dangerous among the listed representatives of the group were themselves ankylosaurs from the suborder ornithischians, which were also called "tank reptiles". These were squat ten-meter armored dinosaurs with a wide head, a powerful body, reliably protected by strong armor, and a tail with a dangerous tip in the form of a mace.

One of the most mysterious dinosaurs. The meager number of fossils found (and this after 150 years of world fame) only enhances this effect. The classification was also constantly revised. Lived at the end of Maastricht. Latin name comes from the ancient Greek words - thick-headed lizard. The evolution and purpose of the robust, dome-shaped skull is still debated.

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Time and place of existence

There were pachycephalosaurs at the end Cretaceous period, about 70 - 65.5 million years ago (Maastrichtian stage). They were common in the northern United States. In particular, these are the states of Wyoming, Montana and South Dakota.

Three-dimensional image of a dinosaur on a rocky ledge, created by Vlad Konstantinov.

Types and history of discovery

Nowadays one type is known - Pachycephalosaurus wyomingensis, which is accordingly typical.

Scientist Donald Byrd claims that, by all indications, the first fragmentary finds of a pachycephalosaur were made back in 1859 or 1860 by the American geologist Ferdinand Hayden. The fossil was discovered near the headwaters of the Missouri River in southeastern Montana (now a large geological formation called the Lance). The specimen received ANSP ID 8568 and was described by Joseph Leidy as a piece of the outer armor of an unknown reptile or armadillo-like mammal. Rod got a name stilly(Tylosteus). For a number of reasons (primarily due to the poor diagnosability of the fragment), it is not currently used as a priority.

Officially, the type species of Pachycephalosaurus was described by the American paleontologist Charles Gilmore on the basis of a partially preserved skull (specimen USNM 12031) in 1931. It is easy to guess that the name wyomingensis was given to it in honor of the place of discovery, the state of Wyoming.

Dracorex and Stygimoloch - juvenile pachycephalosaurs?

Just recently, in 2007, the well-known American paleontologist, professor at the University of Montana John Horner, expressed the revolutionary idea that pachycephalosaurids Dracorex And Stygimoloch are not at all independent childbirth. In his opinion, these are young specimens of pachycephalosaurus!

First, let's say that they were found and classified as separate structural units on the basis of the following differences from the real pachycephalosaur: the skulls are less domed and flatter, the spines in the nose are pointed, and on the back of the head they are real small horns. According to the professor, the latter did not increase with age, but decreased! At the same time, the skull developed until it turned into the round structure familiar to everyone. Horner's theory is supported by the dating of the geological layers in which all three dinosaurs were found. Judging by them, they lived in the same temporary area.

In 2009, the official scientific work of John Horner and Mark Goodwin was published with detailed analysis this version. We believe that the grounds are more than compelling, but we are waiting for additional evidence to make a verdict. If the scientists’ hypothesis turns out to be correct, then this will be a colossal breakthrough not only in the field of anatomy of dinosaurs, but also other prehistoric animals. What will lead to revision large quantity known genera. In particular, the option is already being considered in which the pachycephalosaurid homalocephalus is nothing more than a juvenile prenocephalus.

Body structure

The body length of the pachycephalosaurus reached 4.5 meters. The height is up to 2 meters. He weighed up to 450 kilograms.

It is the largest genus of all known pachycephalosaurs. However, it is important to note that the exact length of the body is still unknown. This is due to the fact that the remains found throughout this time are a complete skull and other fragments of the head part. Therefore, the previous range of estimates was enormous: from 3 to 12 meters. Only after the remains of Dracorex and Stygimoloch were found, the anatomy of the animal became more or less clear. The most recent length estimates based on the latter are about 4.5 m.

He walked on two legs. The forelimbs were small, but quite developed. With them he held the bushes or even picked fruits.

Now let's turn to the most interesting area of ​​the pachycephalosaur: the dome-shaped skull, decorated in the occipital and nasal parts with bony horn-like outgrowths. They were blunt, so they were a common decoration. The thickness of the dome itself reached 25 centimeters! What was the purpose of such an impressive instrument that reliably protected the dinosaur’s small brain?

Option one: it is assumed that it was particularly spectacular mating season these animals, when the males first showed off headdresses with various bone growths, and then literally banged their heads for the females. Thick skulls easily withstood such a load. But, as with modern animals, it was more of a demonstrative and ceremonial nature, and usually it ended without serious injuries. Option two: protection from small and medium-sized predators.

We believe that both cases occurred. Classic versatility, like most mammals with large horns.

The long tail of an animal adapted to fast movement, was extended parallel to the ground.

Has a number common features both with representatives of the suborder of ornithopods and with representatives of ceratopsians. However, it cannot be counted among the above, because it has a rather unique body structure. Therefore, we distinguish a separate suborder of pachycephalosaurs (the name is in honor of the very first representative).

American artist Laurel Austin sees the Pachycephalosaurus more densely.

Pachycephalosaurus skeleton

The photo shows a reconstruction of the species Pachycephalosaurus wyomingensis, which is at the disposal of the Barpee Museum of Natural History (Rockford, Illinois, USA).

Below is a skull from the Oxford University Natural History Museum (England).

Nutrition and lifestyle

It is still not clear what kind of food pachycephalosaurs consumed. The rather small teeth are not designed for tough vegetation such as tree trunks, roots or branches. Viscous fibrous samples would also not be to their taste.

Scenic painting by Brazilian artist Julio Lacerda. The Maastricht lizard is greeted by a cool mountain morning and lush magnolia blossoms.

From all this it follows that, most likely, they were real gourmets and looked for the soft, juicy foliage of flowering plants or young needles. It is possible that any edible fruits, in particular fruits and vegetables, were used. The seeds could also be digested without difficulty.

It is quite likely that pachycephalosaurs were united in groups. Possessing a good “cranial” weapon, they were able to protect their offspring from at least small and medium-sized predators. From giants such as adult tyrannosaurs, only their senses and legs could save them.

During the mating season, they showed off in front of the females and tested the strength of their armored heads.

Giovanni Caselli's drawing demonstrates this amazing process.

Video

Excerpt from the television documentary series "Deadly Dinosaurs" (2018). The duel of adult pachycephalosaurs is shown in all its glory.

The ankylosaur was real tank of the Mesozoic era. Its body was covered with powerful armor, and on its tail there was a powerful bone bump. Ankylosaurus was dangerous even for a ferocious tyrannosaurus or Albertosaurus. Ankylosaurs received their name in honor of the characteristic curvature, sharp concavity of the body ribs outward (translated from Greek, curved, curved)

The head at the base of the skull was protected by triangular-shaped bony protrusions. The teeth were located deep in the mouth and were very small. The jaws were poorly developed, but were still suitable for chewing soft plant food.

Limbs and body structure:

Ankylosaurs - large dinosaurs moving on four short and powerful legs. The ankylosaur's body was as long as a bus.

The ankylosaur had a large, heavy bony "club" at the end of its tail. The size of the mace was approximately 5-6 times larger than a human head. Swinging such a mace, the dinosaur could deliver incredible blows to its enemies.
The dinosaur looked flattened on top and would even resemble a turtle, if not for its powerful tail with a heavy bone club at the end. The dinosaur's tail, with a club at the end, was driven by muscles located at the base of the tail.

Protection:

Ankylosaurus lived at the same time as dinosaurs such as Tyrannosaurus and Albertosaurus. This is most likely the reason for such equipment. The Ankylosaurus was practically unapproachable from above. Given the rise of predatory therapods at the time, the ankylosaur was ideally protected.
Noticing the danger, the ankylosaur immediately went on the defensive. The ankylosaur's brain was tiny. Therefore, in case of danger, it could automatically attack theropods.

The dinosaur turned sideways to the attacker and, swinging its mace-tail from side to side, waited for the moment to strike. With one such blow, the ankylosaur could not only make it clear to theropod predators that it was unlikely to have lunch here, but even seriously injure the attacker. With one blow, the ankylosaur could break a bone or damage internal organs predatory dinosaur.

Despite this seemingly invulnerability, the ankylosaur had a weak point. The fact is that the armor only covered the upper half of the dinosaur. The ankylosaur's belly was not protected. If predators managed to turn the ankylosaur onto its back, it had no chance of salvation.
But turning over a dinosaur weighing 4 tons is not an easy task.

Lifestyle:

Herbivorous dinosaurs often lead a herd lifestyle. This helps them protect themselves from predatory dinosaurs. To date, paleontologists have not discovered a massive accumulation of remains of ankylosaurs, as was the case with Triceratops. Most likely, ankylosaurs lived alone.

Ankylosaurs may have had very few young. At the end of the Cretaceous period, this became a common problem among all dinosaurs. According to scientists, this is due to changes in the environment.
Adult ankylosaurs could live for a very long time because their armor and spines made them virtually invulnerable. Good protection and was the key to the success of ankylosaurs.

Parasaurolophus(Parasaurolophus) is a dinosaur from the family of hadrosaurs (hadrosaurids), the so-called “duck-billed” dinosaurs from the suborder of ornithopods.

This herbivorous dinosaur with a duck beak lived 76-73 million years ago (end of the Cretaceous period) in the territory of modern North America. On his head there was a hollow tube-like growth; perhaps it was longer in males.

The most characteristic part of the parasaurolophus body was undoubtedly the tubular growth on the head

Cavity theory

Most paleontologists now agree that Parasaurolophus could have used its hollow crest to produce a moo; blowing air through two or four tubes passing inside the outgrowth produced a low, long sound.

At the same time, the outgrowth could perform other functions. The theory initially put forward suggested that the hollow tube could be used in a similar way to a scuba diver's breathing tube when diving into water.

If this assumption was correct, then the outgrowth should have had cavities for storing air reserves. This theory is now considered unlikely.

Another possible explanation is that the protuberance may have been attached in such a way that it could be tilted back, pressing against the parasaurolophus' neck. This skill could be useful when running through dense thickets, since the outgrowth pressed in this way did not touch overhanging branches.

It is unknown what color the parasaurolophus was, so artists give free rein to their imagination

Such theories are not easy to prove. But few doubt that Parasaurolophus could really make loud sounds by blowing air through its crest.

This assumption was tested experimentally: scientists constructed a model of the tubular outgrowth of a parasaurolophus and passed air through it, resulting in a deep, booming roar.

Features of the skull

At the back of the skull, Parasaurolophus had a very thin ear bone, indicating that this dinosaur had good hearing.

Scientists noticed that the tubes passing inside the outgrowth are connected to the nostrils of the parasaurolophus. He may also have had a very keen sense of smell.

The front of the mouth was a beak, which Parasaurolophus could use to pluck leaves and other vegetation. The beak was similar to a duck's, but much harder and sharper, more like a turtle's beak.

The rear of Parasaurolophus's upper mandibles contained many small, rhombic-shaped molars that formed grater-like surfaces.

There are three known species of parasaurolophus.

Interesting skeleton

The strong and durable bones of the parasaurolophus indicated that its body was massive and powerful. Of greatest interest was the unusual structure of the forelimbs of the parasaurolophus: shorter than the hind limbs, they naturally served as arms, but the lizard could not only lean on them, but tear off branches and leaves, eating plant food.

In addition, the flat, blade-shaped hands that ended the Parasaurolophus's forelimbs have led some scientists to speculate that it may have used them for swimming.

Parasaurolophus weighed about three tons - about the same as a modern adult elephant weighs - and the bones of its legs and feet must have been strong enough to support the weight of its body.

Like most other hadrosaurs, the bones extending from the spine of Parasaurolophus were held together by a network of strong tendons. The tendons that wrapped around the femurs were especially large.

A long thin bone extending down from the base of the tail made it possible to hold it in weight and thereby maintain balance when the parasaurolophus stood on its hind legs to reach high branches.

Apparently, the parasaurolophus was good at controlling its tail and, on occasion, used it as a weapon.

Relatives

Relatives of Parasaurolophus are Lambeosaurus, which has a rounded growth directed forward on its head, and Corythosaurus, which has a thin plate-like crest on its head.

Corythosaurus

Saurolophus, after whom Parasaurolophus was named, also lived in North America from the Cretaceous period, but was also found in Mongolia. However, its head growth resembled more of an ordinary straight horn.